The defensive unit has been far from great, but compared to what was on the field in 2009 the improvement has been dramatic. NC State ranked sixth in the ACC in total defense with 350.4 yards allowed per contest through Oct. 18 and was giving up 23.7 points per game.

Compare those numbers to 2009 when State allowed 361.2 yards per game and gave up 31.2 points per contest. NC State also has the best third-down defense in the ACC, allowing a 28.7 percent conversion rate, compared to 42.5 percent last year.

The return of fifth-year senior linebacker Nate Irving to the lineup, as well as the development of redshirt junior Audie Cole and redshirt sophomore Terrell Manning, has given the Pack one of the ACC's top linebacking corps. Irving was named the Walter Camp Foundation Defensive Player of the Week Sept. 26 after making 16 tackles, including 4.5 for loss and two sacks, during NC State's 45-28 win at Georgia Tech Sept. 25. He was also named the league's Defensive Lineman of the Week.

Cole was named the conference's Defensive Back of the Week after making 12 tackles, including 3.5 for loss and a sack, and intercepting a pass in State's win at Central Florida Sept. 11. Three of Cole's tackles in that game came on third down and forced the Knights to punt.

Whether it's the maturation of the front seven or the arrival of linebackers coach Jon Tenuta, who is renowned for his blitzing schemes, NC State has been much more aggressive on defense. Through Oct. 18, the Pack was second in the ACC with 21 sacks. Last year, State had 24 sacks in 12 games. The Pack has also forced 17 turnovers, second most in the ACC and already three more than the 14 turnovers State had in 12 games last year.

The secondary has been boosted by the arrival of a trio of talented true freshmen. Cornerback David Amerson supplanted redshirt junior Justin Byers as a starter Oct. 2 against Virginia Tech. Safety Dontae Johnson started against Boston College a week later in place of sophomore Brandan Bishop, who leads the team with three interceptions. Safety D.J. Green has also earned playing time.

The secondary remains very young, but it has held up reasonably well through the first half of the season.

"I think we're much better than we were a year ago," O'Brien said of the defensive backfield. "I think we understand the concepts much better. Last year, we spent a lot of time coaching on the run and coaching kids that weren't really ready to play the game and that would have been better off being redshirted. But due to injuries and lack of depth they had to play.

"I think through spring practice and summer camp they have a much better understanding of what the concepts are and what we're asking them to do, and subsequently they are in much better position, and they are lined up better. They're reactions are better. They are anticipating."

One of the questions that remains to be answered is whether or not sophomore cornerback Jarvis Byrd will return to the team this fall. Byrd tore his ACL against North Carolina in the 2009 season finale, but he has made a quick enough recovery to resume running and conditioning work in October. O'Brien has not committed to redshirting Byrd for this season, but the option looks increasingly likely while the Pack enters the stretch drive of the season.

Two areas that will need improvement for NC State are cutting down the number of big plays allowed and the rush defense. While the Pack seems to be winning the battles in the trenches, big plays have led to most of the touchdowns allowed by State's defense. In games two through seven, State allowed 16 touchdowns. Ten of those drives were sparked by plays that went at least 31 yards. Seven of those 10 drives had a gain of at least 50 yards. Four of the six touchdowns that were not the result directly or indirectly of a big play were set up by good field position where the opposing team's longest drive was 53 yards.

NC State is also allowing 143.4 rushing yards per game, which is fifth in the ACC. That number is a bit skewed, however, by the opponents.

Both Central Florida and Cincinnati were missing their top running backs with injuries, and Western Carolina was an inferior opponent. Boston College's tremendous struggles at the quarterback position has nullified its rushing attack, and East Carolina is a predominantly passing team.

Virginia Tech and Georgia Tech ran for 317 and 247 yards, respectively, and the Hokies in particular were effective running the ball.

Grading the defense: The Pack has been much more aggressive, leading to more turnovers, and unlike 2009 NC State is getting off the field on third downs. The defense still has some areas in need of improvement, and the scoring defense is only eighth in the ACC, but the difference between 2009 and 2010 is eye-catching. Grade: B